#1176: refuse to delete from a fact that is no longer in the factbase

lib/fbe/delete.rb

@@ -34,6 +34,7 @@ def Fbe.delete(fact, *props, fb: Fbe.fb, id: '_id') # rubocop:disable Metrics/Cy
   end
   fb.txn do |fbt|
     deleted = fbt.query("(eq #{id} #{i})").delete!
+    raise(Fbe::Error, "No facts by #{id} = #{i}") if deleted.zero?
     raise(Fbe::Error, "#{deleted} facts share #{id} = #{i}, cannot delete one of them") if deleted > 1
     c = fbt.insert
     f = c

lib/fbe/delete_one.rb

@@ -18,7 +18,7 @@
 # @param [Factbase] fb The factbase to use (defaults to Fbe.fb)
 # @param [String] id The property name used as unique identifier (defaults to '_id')
 # @return [nil] Nothing
-def Fbe.delete_one(fact, prop, value, fb: Fbe.fb, id: '_id')
+def Fbe.delete_one(fact, prop, value, fb: Fbe.fb, id: '_id') # rubocop:disable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
   raise(Fbe::Error, 'The fact is nil') if fact.nil?
   prop = prop.to_s
   i = fact[id]
@@ -36,7 +36,7 @@ def Fbe.delete_one(fact, prop, value, fb: Fbe.fb, id: '_id')
   before[prop] = nv
   before.delete(prop) if nv.empty?
   fb.txn do |fbt|
-    fbt.query("(eq #{id} #{i})").delete!
+    raise(Fbe::Error, "No facts by #{id} = #{i}") if fbt.query("(eq #{id} #{i})").delete!.zero?
     c = fbt.insert
     f = c
     while f.instance_variable_defined?(:@fact) || f.instance_variable_defined?(:@origin)

test/fbe/test_delete.rb

@@ -15,6 +15,17 @@
 # Copyright:: Copyright (c) 2024-2026 Zerocracy
 # License:: MIT
 class TestDelete < Fbe::Test
+  def test_refuses_to_bring_back_a_removed_fact
+    fb = Factbase.new
+    f = fb.insert
+    f._id = 1
+    f.k = 1
+    f.t = 5
+    fb.query('(eq _id 1)').delete!
+    assert_raises(Fbe::Error) { Fbe.delete(f, 't', fb:) }
+    assert_equal(0, fb.size)
+  end
+
   def test_deletes_one_property
     fb = Factbase.new
     f = fb.insert

test/fbe/test_delete_one.rb

@@ -15,6 +15,17 @@
 # Copyright:: Copyright (c) 2024-2026 Zerocracy
 # License:: MIT
 class TestDeleteOne < Fbe::Test
+  def test_refuses_to_bring_back_a_removed_fact
+    fb = Factbase.new
+    f = fb.insert
+    f._id = 1
+    f.k = 1
+    f.t = 5
+    fb.query('(eq _id 1)').delete!
+    assert_raises(Fbe::Error) { Fbe.delete_one(f, 't', 5, fb:) }
+    assert_equal(0, fb.size)
+  end
+
   def test_deletes_one_value
     fb = Factbase.new
     f = fb.insert